The expression pattern and role of circulating CXCR5(+) γδ T cells in children with newly diagnosed immune thrombocytopenia.

INTRODUCTION: Immune thrombocytopenia (ITP) is the most common bleeding disorder in children. Tfh cells play a crucial role in the pathogenesis of ITP by promoting the production of anti-platelet autoantibodies. Recent studies have shown that CXCR5(+) γδ T cells not only possess "Tfh-like" cell functions but also can induce Tfh cell differentiation. However, it remains unknown whether CXCR5(+) γδ T cells are involved in the pathogenesis of ITP. This study aims to investigate the role of CXCR5(+) γδ T cells in children with newly diagnosed ITP (nITP). METHODS: A total of 96 children with nITP and 48 healthy children were enrolled in this study. FCM was used to compare the frequencies of circulating CXCR5(+) γδ T cells and circulating Tfh cells, as well as the levels of ICOS and CD40l on circulating CXCR5(+) γδ T cells in both groups. The correlation between circulating CXCR5(+) γδ T cells and platelets as well as circulating Tfh cells were further analyzed. RESULTS: Compared with healthy controls, the frequency of circulating CXCR5(+) γδ T cells was higher in children with nITP, and it was negatively correlated with platelet count. The levels of ICOS and CD40l on circulating CXCR5(+) γδ T cells in children with nITP were also higher. Children with nITP had a higher frequency of circulating Tfh cells, which was positively correlated with circulating CXCR5(+) γδ T cells. CONCLUSIONS: The excessive activation and proliferation of CXCR5(+) γδ T cells may contribute to the pathogenesis of nITP in children. Therefore, it can be used as a target for the immunotherapy of pediatric ITP.